Apparatus for forming perforations in wells



APPARATUS FOR FORMING PERFORATIONS IN WELLS Filed June 15. 1951 Feb. '7, 1956 c. M. BRYANT ET AL 2 Sheets-Sheet l m 5 49 m m y 3 M U W W M m wMcJ m #wa r nfle/ v aW/Z APPARATUS FOR FORMING PERFORATIONS IN WELLS Filed June 13, 1951 Feb. 7, 195% c, M. BRYANT ET AL 2 Sheets-Sheet 2 INVENTORS. Char/65M. Bryan) Wi/bur N. He/be Leo A Cour/er BYCQa e J Ceci/ ATTORNEYS United States Patent 'ice Leo A rtl". Clyde J. Cecil, Oklahoma Qity, Oklfai; ,aSs1gn6i'sjqIhejDowj Chemical Company, Midland} Michi, a corporation of Delaware Application June 13, 1951, Serial No. 231,364 4 dating. (Cl. 102-20 The invention relates to apparatus for forming openin'gs from a well in the earth into the adjacent earth formation. It inore particularly concerns an improved apparatus for perforating casing in earth wells, the c'eirien't sheath, if any, around the easing, and also the wall of the well hole Beyond the casing and cement sheath, involving the use of Bi detonz'iting eXp'l'Os'i'Ve charge which is hollowed so as to direct the explosive force rnainly in a direction outwardly from the hollow.

In View of the strong piercing action of detonating explosives when suitably shaped, as hy forining a conical hollow in one end of the charge and preferably lining the hollow with a metallic sheath, their usefo'r forming perforatio'n's in Wells has become general. However, a her of disadvaiit'ages' inure to the conventional device's used for the purpose employing the shaped explosive charge which lirhits their usefulness.

Accordingly, the principal object-of the invention is to provide an improved apparatus using theshaped explbs ve charge; having a directional explosive eliect, foiforniing an opening from the interior of a well through casing therein or into the adjacent earth formation or both.

A particular object of the invention is to provide a frangible enclosure for the shaped explosive charge and a frangible carrier therefor adapted to carry one or more of the enclosed shaped explosive charges suitably orie'n'tated as to their directiofial explosive effect, the enclostires and carrier being totally expendable in the periprating-ope ra'tion without producing debris in the Well involving either a drilling or a fishing operation for removal. I

A further object is to provide in'eans of the foregoing character which perrn'its the use of larger shaped ex losive charges having deeper and more powerful piercing action than conventional perforating apparatus.

Still another object is to provide means of the foregoing character which readily permits adjustment of the relative levels o'f'the explosive charges on the carrier.

Other objects and advantages will become apparent from the following description and annexed drawing, showing' hy way of example but not of limitation, the ap aratus arranged for producing three perforations at one firing operation.

In are said drawing, I I

Fig. 1 is a side elevation of the assembled apparatus prdvided with threeenclosjed shaped explosive charges, each at a different level, and each having the firirig axis oriented in a direction different from one another, that of the uppermost charge facing the observer.

2 a' cross section on the line 2--2 of Fig. l. I

Fig. 3 is a rear elevation of a portion of Fig. I showing the reai of one of the frangible containers mounted in the carrier. v t

Fig. 4 is a cross section on the time 4 4 of Fig. 3.

Fig. 5 is: a cross Se a-on an the line s 5 or Fig. 1.

i i the drawing, like 'iiuiiiefals desigtiat'ed like parts.

Referring to the drawing" in geiieriil, but more particu- 36 within the cover.

- and;1'n a plane perpendicular to" the a of the c 2,733,657 Patented Fla 1, 1956 may :6 Fig. I; there is shes/1i aperz iun of a well casing 1 to he' s; ed the plurality at lavas. suspended in the Well by cable 2 ithe permitting" app ifivei'ifid Which iiiifdlv'e s thre' infi'felatd tifiits, viz. 1 a detoniitdr ties-c t2 fra gilile expendable carnet or fr'aine 4' arid (3) f ible ip'efidabl'c cohfaincls 5 for the fies, the COl'liEillllS being ""i iited iii the frame at various levels and var ously or eiit'a "d t v T seil'ifits Will iii w be' dsciili'ed'. 56 V prises a liousiiig 6, of generally 63'' w threadedly sec'ur''d tib a S fiauyinreada fewer did to of th sin V A Passages 11, 12, and 13 are piovided through plug 8, the lower ends l l, 15, and 16 respectively, of which are iiitriially mresda. Externa ly threaded bushings 11, is, and 19 are screwed into the iii'ternally threaded lower ends 14', .15, and 16, respectively.

(2) The .carrier orfrafire 4 comprises three tubular members 20, 2-1, and 22' symmetrically disposed in a t-riangular arrangement by upper and lowef triangular braces 23 and 24; respectively. The upper" ends of the tubular members above the" upper brace 23 are befit inwardly and secured in bushings 17, 18, and 19 by the Eouplings 25, 26-, and 27;, respectively Their ldvver ends 28, 29; and 30, respectively,= below the lower brace 24, are bentinwardly to provide a pointed lower end for the frame. Between the upper and lower ends; the tubular members are straight andspaced equally frorii each other} The tubula r members are made of thirrwall tubing, the bore of which will perrhit the threading therein of a detonable fuse; such as'. pritiia" cord.

(3) As shown; the frame 4 carries three frangible containerspn the straight parallel portions of the tubular mernbers 20,21 and 2 2','.althot'rgl1 a greater 01f lesser number can, be accommodated by makingthe tubular members of appropriate length. Eachcontaiher' is molded wholly .ci a frangible i'irflteiial as glassj 1 W1 0 cup-shaped thick-walled firemb ers 31 and 32,- tliei ter being regarded as a coverfo'r the former which is referred to as a, receptacle. Bot-h the receptacle ahd the cover have cylindrical inside. wall surfaces 33 arid- 34,- ife ectively, the portion of the inside wall nearer the openend oi the cover beingof the same diameter macaw-.2 11 of the receptacle. The remainingportioii 351 61? the cylindrical inside wall of the'cover is of smaller diatiieter and concentric with the larger diai'iiet'er portion, the junctionof. the two portions forming iiiilai'j shfihlder I The oii't s'ide of the ends 37 aid 38 of the receptacle and cover, respectively, are donieshaped and the sides generally cyliit" teat so as to resist strong external fluid pressures. The in de of the icceptacle has a fiat aimu'lar bottom por arecess 40 in the i'niddle; I A has a; groove 41 across the iniddl'e of theatre 37' leavn'i bottom; f; the groove and the hottdm 6f the recess about 0.04 m 0.2-5 inch thick. The greov'e is of s circular cross section adapted to allow a-tiibulai' inernberto lie in it; The sidewalls 43 and 44 of the receptacle and; cover, respectively, have their open ends made flat V, 7 "v i, s e surfaces 33 and 34 to form the planar (preferahly ground) suriacesjld; and 116,: respectively.

l e cover is' provided with 'apair of bos's'es' 47 and 48, n olded offrangible material; diametrically oppo 'e to each; otheron ;t he outside or the sidewall 44,- the iiiiddle of the bosses being on a line perpendicular to the axis aratus of the of the cylindrical inside wall 34. The bosses are provided with grooves 49 and 50, respectively, of similar form to groove 41 and perpendicular to the plane in which lie the aforesaid axis and line perpendicular thereto.

Referring more particularly to the shaped explosive charges, one of which 51, is illustrated in section in Figs. 2 and 4 (together with a booster charge 52), it will be seen that the shaped charges are generally of cylindrical form. One end is hollowed out as by a conical recess 53 which is usually lined, as with a cone 54 of sheet metal or other inert material. The dimensions of the receptacle and cover, particularly the insides thereof, are determined by the diameter and length of the shaped charge to be thereby enclosed. And the length of the cylindrical inside surfaces 33 and 34 taken together are made to accommodate the length of the charge. The distance from the shoulder 36 to the end 38 of the cover should be sufficient to provide an unobstructed space 55 for the shaped charge to function in its intended manner when placed in the receptacle and held therein by the cover, the distance generally being about 50 per cent of the length of the shaped charge.

Loading, mounting, and fusing the containers on the carrier frame As already indicated, a booster charge 52 is placed in the recess 40 of a receptacle 31 and thenthe shaped charge 51 is fitted into the receptacles so that the hollowed out end of the charge or recess 53 faces outwardly. A cover 32 is placed over the charge allowing the shoulder 36 to engage the rim 56 of the cone 54, and, the flat surfaces 45 and 46, to butt together. A caulking compound is applied, as a band 57, on the periphery of the junction of the two'surfaces 45 and 46 to seal the juncture against 'number of containers is accomplished before installing the lower brace 24 and before the ends 28 and 29 and 30 of the frame members are bent inwardly, thus: with the upper brace 23 in place, the uppermost loaded container is placed between the frame members 20, 21, and 22 so that their straight portions lodge in the grooves 49, 41, and 50, respectively. The frame members are then bound in place in the grooves as by strap 58, the ends of which are secured together as by a buckle 59. A spacer tube 60 is slipped over one of the frame members, e. g. 20, and then a second loaded container is strapped to the frame below the uppermost container, as shown. The second container may be orientated so that the firing axis is directed 120 degrees away from the firing axis of the first loaded container, as in the arrangement shown. A third loaded container, and still others, may be added in similar manner to the frame with suitable length spacers in between. These spacers are preferably staggered, and, in the example shown with three containers, the second spacer 61 is placed on a different frame member from the first below the second container. After the desired number of containers is mounted in the frame and suitably spaced from one another along the frame, the bottom brace, e. g. 24, is slipped over the lower ends of the frame members 28, 29, and 30, respectively, which thereafter preferably are bent inwardly as shown, thereby holding the brace 24 in place. It will be evident that in some cases the straps 58 may be omitted and the trilateral braces 23 and 24 relied upon for holding the frame members against the enclosures. Again, the trilateral braces 23 and 24 may be omitted if desired and the enclosures 5 and strap means 58 relied upon for spacing the frame members from each other and holding them against the enclosures.

In order to fire each explosive charge and destroy the frame detonating explosive fuses 62, 63, and 64, such as a prirna cord having a uniform rate of detonation per unit of length, is threaded through each of the tubular frame nificant damage.

members. A length of detonating fuse thereby passes in close proximity to the booster charge in each container. The upper ends 65, 66, and 67 of the fuses are brought together in the detonator housing 6 and bound together as with adhesive tape 68. One of the ends, e. g. 67, is made longer than the others and to it is fastened a detonator 69, e. g. a blasting cap, as by adhesive tape 70. Electrical leads 71 and 72 from the detonator 69 connect with the insulated conductor 73 of the cable and the housing 6, respectively. With this arrangement, the cable 2 is provided with a metallic sheath 74 which is fastened in the cable socket 7 and thereby grounded to the housing 6 so as to provide two current leads to the top of the well for actuating the detonator in the usual way.

In operation, the loaded apparatus is lowered into the well to the level at which it is desired to make the perforations from the interior of the well through the casing, if any, into the adjacent earth formation. After locating the apparatus at the desired level in the well, a suitable potential is applied between the conductor 73 and cable sheath 74 to fire the detonator 69. This in turn explodes the detonating fuse 67 and the others 66 and 65 bound to it. The exploding fuses 65, 66, and 67, which extend down the frame members to the groove in the receptacle member of the containers and in close proximity to the booster charges, e. g. 52, detonate the boosters adjacent to the respective fuses. The boosters in turn detonate the shaped charges, e. g. 51, in each container. A piercing explosion proceeds from the hollowed end of the shaped charges along their axes into the area adjacent thereto forming the desired perforation (not shown) in the wall of the well, and easing therein if any. To obtain an adequate piercing efiect, suflicient space 55 is allowed between the hollow 53 and the inside of the end 38 to the cover 32 in each container, as understood in the art of using the shaped charge which utilizes the Monroe effect as in this instance. The explosions which occur shatter the frame members 20, 21, and 22, the bores of which are loaded with detonating fuse, the braces 23 and 24 adjacent thereto, and the spacers 60 and 61. All these parts may be made of aluminum, magnesium and their alloys, for example, which shatter into small fragments. The containers being of frangible material, such as glass, also shatter into fine particles leaving no obstructing matter in the well hole requiring either a fishing or drilling operation for removal. The detonator head 4 is made rugged enough to withstand the explosion of the detonator and the portions of detonating fuses therein without sig- The bushings 17, 18, and 19 and the threaded boss 9 sometimes become damaged and then need to be replaced after use along with the couplings 25, 26, and 27 which become shattered in the explosion.

It is desirable, if not necessary, to seal the lower ends 28, 29, and 30 of the tubular members, as by plugs 75, 76, and 77 respectively, against ingress of fluid which would adversely affect the action of the detonable fuse in the tubular members.

We have found that a plurality of charges of 1 to 8 ounces of shaped high explosive may be set off with the apparatus without detrimental mutual interference, thereby deeply piercing the well wall, with spacing between the containers of 3.5 inches. A 4 ounce charge is generally suitable for most operations and these may be spaced about 3 to a foot of carrier length, although other size charges and spacings may be used.

We claim:

1. An apparatus for forming perforations in a well by means of a shaped detonable explosive charge comprising a housing having a cylindrical body portion adapted to contain a detonator; a removable upper closure for the upper end of the housing; a removable lower closure for the lower end of the housing, said lower closure having downwardly extending passages therethrough communicating with the interior of the housing; tubular members having their upper ends secured to the lower closure with their bores communicating with the said passages, said tubular members and passage; being adapted to contain a detonating explosive fuse extending from the detonator through the passages and bores of the tubular members; a frangible container adapted to enclose a shaped detonable explosive charge having a hollowed portion on one side so as to produce a piercing explosion in a direction out of the hollowed portion, said container consisting of a receptacle for the detonable explosive charge and a cover therefor, said receptacle having a groove in the outside of the bottom thereof, said cover having a pair of similar grooves in bosses on opposite sides of the cover, said grooves being adapted to engage the tubular members; and binding means for securing in each groove one of the said tubular members.

2. An apparatus for piercing a well wall comprising a housing adapted to contain a detonator or blasting cap, said housing having an access opening at the top and bottom; removable closures for the access openings, the closure for the bottom access opening having three downwardly extending passages therethrough; a trifurcated frame of tubular members having straight parallel portions intermediate the ends; means for securing the upper ends of the tubular members to the closure for the bottom of the housing with the bores of the tubular members in communication with the passages; frangible containers adapted to contain a shaped detonable explosive charge, said frangible containers comprising a cup-shaped frangible receptacle for the charge, and a cup-shaped frangible cover for the receptacle with their open ends butted together, said receptacle having a groove diametrically across the outside of the bottom; bosses disposed on opposite sides of the cover, the outer end of each of said bosses having a groove therein, the said grooves in the bosses and receptacle being adapted to permit the tubular members to lodge therein; and means to hold the tubular frame members in the said grooves.

3. An apparatus for piercing a well wall employing shaped detonable explosive charges for producing the piercing comprising ahousing having an access opening at the top and bottom, said housing being adapted to contain a detonator or blasting cap; removable closures for the top and bottom openings of the housing, the closure for the bottom opening having downwardly extending passages therethrough communicating with the interior of the housing; a trifurcated frame of tubular members having portions intermediate their ends parallel to each other, the upper ends of the tubular members being secured to the removable bottom closure with their bores in communication with the passages, said tubular members and passages being adapted to contain a detonating fuse extending from a detonator in the housing through the said passages and bores of the tubular members; in-

dividual glass containers each adapted to contain a shaped detonable explosive charge, said containers comprising a cup shaped receptacle for the charge and a cup-shaped cover therefor, said receptacle having a recess in the middle of the inside of the bottom and a groove diametrically across the outside of the bottom, the wall thickness of the receptacle between the bottom of the recess and the bottom of the groove being about 0.04 to 0.25 inch, said cover having a pair of similar grooves in bosses on opposite sides of the cover, said grooves being adapted to engage the tubular members; and means to hold the tubular frame members in the said grooves.

4. In an apparatus for piercing a well wall by means of a shaped detonatingexplosive charge having a directional explosive action, the combination of a two piece frangible container for the explosive and a frangible supporting frame therefor, said frame comprising three frangible tubular members having straight parallel portions intermediate their ends; frangible braces between the members adapted to hold the members in a triangular spacing; a non-frangible detonator housing comprising a cylindrical chamber; a removable closure for the bottom of the chamber, said closure having three passages therethrough; means detachably secured to the closure for securing each tubular member at its upper end to a passage in said closure; at non-frangible removable closure for the upper end of the cylindrical chamber, said removable closure having means for securing the same to a cable for suspending the apparatus in the well, said frangible container having grooves in the external surface thereof, each groove being adapted to receive a tubular member of the frame; means to hold the frame members in the said grooves; a shaped detonable explosive charge in each container; a detonating fuse threaded through each tubular frame member and extending into the detonator housing; and detonating means in the housing adapted to detonate the said fuses to detonate each explosive charge.

References Cited in the file of this patent UNITED STATES PATENTS 82,586 Beach Sept. 29, 1868 2,362,829 Kinley Nov. 14, 1944 2,494,256 Muskat et al. Jan. 10, 1950 2,543,814 Thompson et al Mar. 6, 1951 2,587,244 Sweetman Feb. 26, 1952 2,616,370 Foster Nov. 4, 1952 2,629,325 Sweetman Feb. 24, 1953 2,669,928 Sweetman Feb. 23, 1954 OTHER REFERENCES Article by R. H. McLemore entitled, Casing Perforating With Shaped Explosive Charges, published in The Oil and Gas Journal, issue of December 28, 1946. 

1. AN APPARATUS FOR FORMING PERFORATIONS IN A WELL BY MEANS OF A SHAPED DETONABLE EXPLOSIVE CHARGE COMPRISING A HOUSING HAVING A CYLINDRICAL BODY PORTION ADAPTED TO CONTAIN A DETONATOR; A REMOVABLE UPPER CLOSURE FOR THE UPPER END OF THE HOUSING; A REMOVABLE LOWER CLOSURE FOR FOR THE LOWER END OF THE HOUSING, SAID LOWER CLOSURE HAVING DOWNWARDLY EXTENDING PASSAGES THERETHROUGH COMMUNICATING WITH THE INTERIOR OF THE HOUSING; TUBULAR MEMBERS HAVING THEIR UPPER ENDS SECURED TO THE LOWER CLOSURE WITH THEIR BORES COMMUNICATING FWITH TH ESAID PASSAGES, SAID TUBULAR MEMBERS AND PASSAGES BEING ADAPTED TO CONTAIN A DETONATING EXPLOSIVE FUSE EXTENDING FROM THE DETONATOR THROUGH THE PASSAGE AND BORES OF THE TUBULAR MEMBERS; A FRANGIBLE CONTAINER ADAPTED TO ENCLOSE A SHAPED DETONABLE EXPLOSIVE CHARGE HAVING A HOLLOWED IN A DIRECTION SIDE SO AS TO PRODUCE A PIERCING EXPLOSIION IN A DIRECTION OUT OF THE HOLLOWED PORTION, SAID CONTAINER CONSISTING OF A RECEPTACLE FOR THE DETONABLE EXPLOSIVE CHARGE AND A COVER THEREFOR, SAID RECEPTACLE HAVING A GROOVE IN THE OUTSIDE OF THE BOTTOM THEREOF, SAID COVER HAVING A PAIR OF SIMILAR GROOVES IN BOSSES ON OPPOSITE SIDES OF THE COVER, SAID GROOVES BEING ADAPTED TO ENGAGE THE TUBULAR MEMBERS; AND BINDING MEANS FOR SECURING IN EACH GROOVE ONE OF THE SAID TUBULAR MEMBERS. 